MAINT-11: start or stop the maintenance cycle per battery

maint_start and maint_abort take an optional unit. With two or more batteries
each Batteries card has Start cycle and Stop cycle buttons. One slot per site
stays: a start while a battery cycles is refused and names it (no queue). A
battery that is switched off, an unknown unit, and a stop on a battery that is
not cycling are refused with a plain message. A request with no unit is the
old call. The scheduler and the phase machine are unchanged.

Co-Authored-By: Claude <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Bdqr7PiaHcBnzPituu2yTC

goodwe_controller/app/main.py

@@ -2777,6 +2777,43 @@ class Controller:
             out["sell"] = pm.sell
         return out
 
+    async def _maint_unit_action(self, what, unit, now) -> dict:
+        """MAINT-11: start or abort the maintenance cycle of ONE named battery.
+
+        Returns `{"error", "code", "unit"}` for a refusal and changes nothing.
+        The site keeps its one maintenance slot: a start while any battery
+        holds it is refused (no queue), see DECISIONS/MAINT-11. The phase
+        machine is not touched beyond `force_start()` and `abort()`, the same
+        two calls the bare button makes.
+        """
+        inv = next((i for i in self.inverters if i.name == unit), None)
+        if inv is None:
+            return self._maint_refusal("unit")
+        machine = self.maints[self.inverters.index(inv)]
+        if what == "maint_start":
+            holder = next((i for i, m in zip(self.inverters, self.maints)
+                           if m.phase in POWER_MOVING), None)
+            if holder is not None:
+                return self._maint_refusal("busy", holder.name)
+            if self.modes_on and not self.pack_mode(inv).use:
+                return self._maint_refusal("off", inv.name)
+            for msg in machine.force_start(now):
+                self.log_event(msg, hint=messages.hint(
+                    "maintenance", phase=machine.phase))
+            return {"unit": inv.name, "phase": machine.phase}
+        if machine.phase not in POWER_MOVING:
+            return self._maint_refusal("idle", inv.name)
+        for msg in machine.abort(now, "operator"):
+            self.log_event(msg, hint=messages.hint("maintenance",
+                                                   phase=machine.phase))
+        await self.command_site_zero()
+        return {"unit": inv.name, "phase": machine.phase}
+
+    @staticmethod
+    def _maint_refusal(code, unit="") -> dict:
+        return {"error": messages.maint_refused(code, unit), "code": code,
+                "unit": unit}
+
     def mode_values(self) -> dict:
         """OPT-11 P2: each battery's mode and switch, for their HA state
         topics. Read from the store, so they are right after a restart. Empty
@@ -7513,6 +7550,10 @@ class Controller:
                 # would read as the stop button not working.
                 await self.command_site_zero()
             return {"auto": self.auto}
+        if what in ("maint_start", "maint_abort") and unit is not None:
+            # MAINT-11: the operator named the battery. A request with no unit
+            # falls through to the branches below, unchanged.
+            return await self._maint_unit_action(what, unit, now)
         if what == "maint_start":
             # ⚠️ WHICH PACK, BECAUSE THERE ARE NOW SEVERAL AND THE BUTTON HAS
             # ONE LABEL. `_maint_button()` answers it: the pack that holds the